PREPARATION OF POLY(PYROMELLITIC DIANHYDRIDE-CO-THIONIN) MODIFIED VOLTAMMETRIC SENSOR FOR THE DETERMINATION OF EPICATECHIN

In this study, the electrochemical oxidation of epicatechin and its voltammetric sensing is shown at a sensitive platinum electrode modified with poly(pyromellitic dianhydride-co-thionin). The electrochemical response of the sensor was improved in the presence of both electro-inactive (sucrose, fructose, lactose) and electroactive (gallic acid, cafeic acid, ascorbic acid) interferants and displayed an excellent analytical performance for the determination of epicatechin. A linear response was obtained over a range of epicatechin concentrations from 0.05 mM to 0.30 mM and was shown to be useful for quantifying low levels of epicatechin in phosphate buffer solution, PBS, pH 7.00. Regression coefficient (R2) was found to be to be 0.9969. Limit of detection (LOD) was calculated as 1.8 × 10-5 M by using 3s/m. Where m is the slope of the calibration curve and s is the standard deviation of the calibration graph calculated using the Excel Steyx function.